1. Field of the Invention
The present invention relates to high speed recording and adjacent display of a series of one dimensional image samples of an event taken sequentially during a predetermined time interval.
2. Description of the Prior Art
Events can be studied in several ways. Conventional still photographs capture a two dimensional image of an event in a single instant of time. By employing a succession of still images, an event can be analyzed in two spatial dimensions over a plurality of time increments (i.e., cine photography). To study fast moving events, slow motion photography employs high speed cameras and playback at reduced speeds. High speed photography would have more widespread applicability were it not for certain disadvantages. First, analysis of a transient event that occurs at an unknown time tends to be impractical because of the large amount of film that would be required. For example, were it necessary to operate a high speed photographic camera for one hour before the event occurs, approximately 60 miles of non-reusable photographic film would be required (assuming 16 mm film and a frame rate of 2,000 frames per second). Another disadvantage of photographic film is that it generally does not provide instant accessability of the image. Instead, it must be processed before viewing, a property that renders it unsuitable for applications wherein immediate analysis is required. Still another disadvantage of photographic film relates to the difficulty of computer analysis of data recorded thereon.
An alternative approach to photographic fast frame recording is the use of an electronic camera that includes a solid-state image sensor in combination with magnetic recording means. Such an electronic camera would possess extreme versatility, offering several advantages over the photographic system described above. For example, because magnetic recording media is reusable, it is cost effective even though used in large quantities. In addition, magnetic recording provides immediate playback and is more compatible with computer analysis.
Fast frame recording apparatus is known that combines the high resolution of a photographic film-based system with the versatility of an electronic camera. See, for example, Research Disclosure, Vol. 199, Publication No. 19919, November 1980, published by Industrial Opportunities Ltd., Homewell, Havant, Hampshire, P09 1EF, UK. Such fast frame recorder apparatus records scene information at a high frame rate and plays back the scene information at a slower frame rate for display on a video monitor, thereby producing a slow motion replay of the scene information. However, even the fastest electronic fast frame recorder is capable of only about 2,000 full frames per second or 12,000 partial frames per second (see U.S. Pat. No. 4,339,775; Lemke, July 13, 1982).
For some events, two dimensional spatial image sampling is not necessary, and it is sufficient only to display a series of one dimensional image samples taken sequentially during a predetermined time interval. Such events might for instance include those wherein one wishes to determine the lapse time between events at a plane. For example, the position of horses other than at the finish line is of no concern in a horse race finish, but the sequence of events at the finish line during an extended time period is of concern. One dimensional image sampling is also suitable when information is required of an object's motion in time along only a single spatial dimension, the record being usable much as a graph or chart from which information is gained regarding rate of object motion along that dimension.
There are two types of known cameras for making such records. One is a framing photographic camera which includes a rotating mirror to sweep a beam of light which is modulated in accordance with the image of an event across the surface of a sensitized film. In this camera, the film is exposed in successive steps or frames to produce a series of still pictures or exposures taken in rapid succession during the event. One example of such a camera is disclosed in U.S. Pat. No. 2,400,887 for "High Speed Motion-Picture Camera."
The other type of camera, referred to as a photographic streak camera, sweeps a focused beam over a film or moves the film relative to a beam of light. The resulting exposure is geometrically distorted image on the film.
Although framing and streak cameras have much higher sampling rates than conventional slow motion cine cameras, they still suffer the disadvantages mentioned above with triggering for events occurring randomly, non-reusable film, processing delays, and computer incompatibilities.